Alright So I'm guessing most DMS would ban this combo

School of Necromancy: Inured to Undeath

Beginning at 10th level, you have resistance to necrotic damage, and your hit point maximum can't be reduced. You have spent so much time dealing with undead and the forces that animate them that you have become inured to some of their worst effects.

Spell Aid: 1 action Range: 30 feet Components: V, S, M (a tiny strip of white cloth) Duration: 8 hours Description Your spell bolsters your allies with toughness and resolve. Choose up to three creatures within range. Each target's hit point maximum and current hit points increase by 5 for the duration

I want to try this but, if I had to guess there's a ruling or most dms would ban this interaction

Or am I wrong?